Research Briefs

Research Activities, September 2010, No. 361

Alexander, K. P., and Peterson, E.D. (2010, May). "Minimizing the risks of anticoagulants and platelet inhibitors." (AHRQ grant HS16964) Circulation 121(17), pp. 1960-1970.

In this article, the authors summarize the current state of antithrombotic therapy. They note that thrombosis contributes to many of the problems associated with plaque buildup in the arteries (atherosclerotic disease). They discuss the major anticoagulants and platelet inhibitors approved for use in patients with acute coronary syndromes, their characteristics, and risks. The risks include drug-, patient-, and provider-specific factors related to thrombosis formation or bleeding events. Finally, the authors discuss the future development of safer agents, better monitoring, and clinical process improvement.

Bachhuber, M., Bilker, W. B., Wang, H., and others (2010, May). "Is antiretroviral therapy adherence substantially worse on weekends than weekdays?" (AHRQ grant HS10399). Journal of Acquired Immune Deficiency Syndromes 54(1), pp. 109-110.

In this letter to the editor, the researchers address whether HIV-infected patients adhere to their antiretroviral therapy as well on weekends (defined as from 5 p.m. on Friday to 5 p.m. on Sunday) as they do during the more structured weekdays. A group of 116 HIV-infected patients with low blood levels of HIV RNA (75 copies per ml) while under treatment were followed for up to 12 months. Median adherence to the drug regimen was slightly, but significantly, higher on weekdays (95.3 percent) than on weekends (93.2 percent). This small weekday/weekend difference was unlikely be clinically significant, the researchers said. Although weekends are not necessarily times for clinicians to be concerned about medication adherence, the researchers recommend helping HIV-infected patients develop plans for any periods involving altered routines.

Capps, C., Dranove, D., and Lindrooth, R. C. (2010, January). "Hospital closure and economic efficiency." (AHRQ grant HS10730). Journal of Health Economics 29(1), pp. 87-109.

The researchers present a new framework for assessing the effects of closing hospitals on both social welfare and the local economy. Closing a local hospital reduces patient welfare, primarily in terms of travel time for the patient and friends and family who visit, but tends to reduce local costs. The researchers use five hospital closures in two States to test their framework and find that, on balance, the cost savings from urban hospital closures more than offset the decrease in patient welfare. Because some of the cost savings are shared nationally (for example, by the Medicare program), the total surplus in the local community due to a hospital closure may be less than anticipated, the researchers conclude.

Clark, D. E., Hannan, E. L., and Raudenbush, S. W. (2010, April). "Using a hierarchical model to estimate risk-adjusted mortality for hospitals not included in the reference sample." (AHRQ grant HS15656). HSR: Health Services Research 45(2), pp. 577-587.

The researchers developed a method for any hospital to evaluate patient mortality using a hierarchical logistic regression equation. This equation, which was derived from a reference sample (the American College of Surgeons National Trauma Data Bank), was developed to allow a hospital that is not part of the reference sample to generate a performance score for quality comparison. The researchers validated the estimated algorithm against actual results using standard software.

Clark, M. C., and Diamond, P. M. (2010). "Depression in family caregivers of elders: A theoretical model of caregiver burden, sociotropy, and autonomy." (AHRQ grant HS13750). Research in Nursing and Health 33, pp. 20-34.

To identify caregivers at high risk for depression so they can be assisted in the early stages of caregiving, the researchers sought to assess the usefulness of the diathesis-stress model for family caregivers. This model emphasizes the role of sociotropy (strong concerns about interpersonal relationships) and autonomy (high achievement concerns) as personality factors that may lead to depression through their interaction with a stress event. For this study, 112 caregivers completed questionnaires on depression, caregiving burden, dysfunctional attitudes, and personal style. The results supported the model by showing that the development of depression was precipitated by the activation of dormant vulnerabilities (sociotropy and autonomy) by a stressor (caregiver burden). These personal characteristics can assist in identifying caregivers at high risk of depression.

Dimick, J. B., Osborne, N. H., Hall, B. L., and others (2010). "Risk adjustment for comparing hospital quality with surgery: How many variables are needed?" (AHRQ grant HS17765). Journal of the American College of Surgeons 210, pp. 503-508.

To better engage surgeons and accelerate quality improvement, the American College of Surgeons (ACS) National Surgical Quality Improvement Program (NSQIP) is moving toward sampling a small number of targeted procedures instead of sampling all procedures. By reducing the number of covariates used for patient risk adjustment, this would decrease the burden of data collection and lower the costs to participating hospitals. For the five core general surgery operations examined in the study, the researchers found that procedure-specific hospital quality variables for both morbidity and mortality can be adequately risk-adjusted with a limited number of variables. In the context of the ACS NSQIP, this more limited model will dramatically reduce the burden of data collection for participating hospitals.

Fleishman, J. A., and Cohen, J. W. (2010, April). "Using information on clinical conditions to predict high-cost patients." HSR: Health Services Research 45(2), pp. 532-552. Reprints (AHRQ Publication No. 10-R052) are available from the AHRQ Publications Clearinghouse.

The researchers used nationally representative data from the Medical Expenditure Panel Survey to compare expenditure prediction models. They examined three approaches to incorporating clinical condition information: the prospective risk score generated by the diagnostic cost group (DCG) algorithm, indicators of specific prevalent chronic conditions, and a count of the number of chronic conditions. The DCG risk score provided the greatest improvement in prediction among the sets of variables considered. However, the number of chronic conditions also significantly predicted high-cost cases, controlling for DCG score category. In contrast, separate indicators of specific prevalent diagnoses were significant predictors of high costs when the model excluded the DCG score. However, the set of key condition indicators provided less improvement than the count of chronic conditions when the DCG score was controlled.

France, D. J., Greevy, R. A., Liu, X., and others (2010, March). "Measuring and comparing safety climate in intensive care units." (AHRQ grant HS15934). Medical Care 48(1), pp. 279-284.

The safety attitudes questionnaire (SAQ) has been used extensively to measure safety climate in intensive care units (ICUs) in the United States and abroad since 2000. It measures six domains: teamwork climate, safety climate, perceptions of management, job satisfaction, working conditions, and stress recognition. Using the SAQ, the researchers sought to measure the safety climate in 110 ICUs in 61 hospitals owned and operated by a single for-profit company. A total of 1,502 (43 percent) surveys were completed by physicians, respiratory therapists, pharmacists, managers, and other providers. The study found a positive safety climate that varied significantly between ICUs and provider types. Survey respondents scored perceptions of management and working conditions significantly lower than the other domains of safety climate.

Haukoos, J. S., Witt, M. D., and Lewis, R. J. (2010). "Derivation and reliability of an instrument to estimate medical benefit of emergency treatment." (AHRQ grant HS17526). American Journal of Emergency Medicine 28, pp. 404-411.

The researchers developed and evaluated the reliability of a tool to estimate the medical benefit of emergency treatment compared with routine outpatient care. The results of using the tool to evaluate a patient's medical records for a 30-day period after the initial visit to the emergency department (ED) was a rating of either significant benefit, possible benefit, or unlikely benefit. The instrument was independently applied by multiple investigators to three different groups of ED patients (300 from a general ED population, 300 from a homeless ED population, and 275 from an HIV-infected ED population). When applied individually, the tool exhibited good to excellent reliability. However, when multiple raters applied it using a consensus process, the reliability was excellent to outstanding.

Hill, S., and Miller, G. E. (2010, May). "Health expenditure estimation and functional form: Applications of the generalized gamma and extended estimating equation models." Health Economics 19(5), pp. 608-627. Reprints (AHRQ Publication No.10-R063) are available from the AHRQ Publications Clearinghouse.

The researchers used data from the United States Medical Expenditure Panel Survey to compare different mathematical regression approaches to estimate health expenditures for the elderly and privately insured adults. They compared the bias, predictive accuracy, and marginal effects of generalized gamma models, extended estimating equations (EEEs), and other mathematical forms. The equations were used to estimate models of total health expenditures and prescription drug expenditures for the two populations. The researchers found that it was important to examine their assumptions about the link functions used. The EEE model, which has a flexible link function, performed as well or better than the other models tested.

Hoff, T. (2010, January-March). "Managing the negatives of experience in physician teams." (AHRQ grant HS11697). Health Care Management Review 35(1), pp. 65-76.

This paper examines how overreliance on experience can undermine learning, participation, and entrepreneurship among teams of physicians in health care organizations. The author drew on 100 hours of direct observation of normal workdays for physician teams in two different work settings in an academic medical center. He found three experience-based schemas that physician teams used to structure social relations and perform work. Each of these schemas had the potential for undermining learning, participation, and entrepreneurship in the group. To avoid such undermining, the author suggests that health care organizations promote bureaucratic forms of control that enable physicians to engage learning, participation, and entrepreneurship in their work.

Jolly, S., Kao, C., Bindman, A. B., and others (2010). "Cardiac procedures among American Indians and Alaska natives compared with non-Hispanic whites hospitalized with ischemic heart disease in California." (AHRQ interagency agreement with the Indian Health Service), Journal of General Internal Medicine 25(5), pp. 430-434.

American Indians/Alaska Natives (AI/AN) have a higher rate of heart disease and cardiac-related deaths than whites. To understand the source of this disparity, the researchers compared rates of cardiac procedures among AI/AN with rates for whites. The data on hospitalizations for ischemic heart disease (796 for AI/AN and 90,971 for whites) was collected in 37 of 58 California counties during 1998-2002. The researchers did not find lower rates for AI/AN than for whites for cardiac catheterization and percutaneous cardiac intervention. Adjustment for age, sex, comorbidities, and payer source did not result in significant differences. Additional research is needed to identify the source of the disparities, conclude the researchers.

Koopman, R.J. (2010, May). "Health and information technology evaluation and education: Finding our way." (AHRQ grant HS17948). Family Medicine 42(5), pp. 312-313.

The article serves as an introduction to a special issue of the Journal on Health Information Technology. The author puts the issue in context, noting that use of health information technology (IT) promises benefits, but can have unintended consequences. She gives brief previews of the topics covered in the issue, such as training family practice residents in use of this technology, the impact of electronic medical records on workflow and physician efficiency, the promise of electronic clinical decision support systems, and the impact of health IT on doctor-patient interactions.

Kreuter, F., Olson, K., Wagner, J., and others (2010). "Using proxy measures and other correlates of survey outcomes to adjust for non-response: Examples from multiple surveys." Journal of the Royal Statistical Society 173 (Pt. 2), pp. 389-407. Reprints (AHRQ Publication No. 10-R058) are available from the AHRQ Publications Clearinghouse.

Household surveys in many countries have witnessed a decline in response rates over the past few decades. The danger of a low response rate is the presence of nonresponse bias if sampled people who are unlikely to participate in a survey differ systematically from participants with regard to survey outcomes of interest. Weighting is one strategy used to address potential nonresponse. However, weighting is effective only when the variables used in constructing weights are highly correlated with both the survey variables of interest and the response propensity. The researchers examined traditional covariates and new auxiliary variables, such as interviewer observations, for five major American and European surveys. Their results show the difficulty of finding suitable covariates for nonresponse adjustment and the need to improve the quality of auxiliary data.

Li, Y., Schnelle, J., Spector, W. D., and others (2010). "The 'Nursing Home Compare' measure of urinary/fecal incontinence: Cross-sectional variation, stability over time, and the impact of case mix." HSR: Health Services Research 45(1), pp. 79-97. Reprints (AHRQ Publication No. 10-R050) are available from the AHRQ Publications Clearinghouse.

The Centers for Medicare & Medicaid Services (CMS) maintain a Web site titled "Nursing Home Compare" that publishes outcome measures derived from resident health assessments. These nursing home quality measures (QMs) should reflect true performance differences between facilities. However, facility variation in QM rates may be affected by varying facility case mix as well as varying care practices. The researchers assessed the potential impact of facility case mix on both the cross-sectional (or between-facility) variations and short-term stability of the CMS QM for urinary/fecal incontinence. They found that at least half of the between-facility variation of the CMS QM was explained by the facility case mix. In addition, both the CMS QM and case mix showed relatively high stability over the short term and, as a result of minimal risk adjustment of the QM, over 25 percent of its short-term variation was explained by case mix.

Luo, N., Ko, Y., Johnson, J. A., and others (2009). "The association of survey language (Spanish vs. English) with Health Utilities Index and EQ-5D index scores in a United States population sample." (AHRQ grant HS10243). Quality of Life Research 18, pp. 1377-1385.

The researchers compared several multiattribute health status classification systems (MAHSCS) to explore whether variations in their index scores were associated with the survey language (Spanish vs. English). The three MAHSCSs compared included the EQ-5D, the Health Utilities Index (HUI) Mark II (HUI2), and HUI Mark III (HUI3). These questionnaires are all preference-based health-related quality of life measures and are available in English, Spanish, and other languages. The researchers found that the EQ-5D and the HUI2/3 health indices exhibited different outcomes in comparison with Hispanic and non-Hispanic American residents, suggesting that the choice of surveys matters when comparing culturally diverse populations. For example, Hispanics taking the HUI2/3 in Spanish were less likely than non-Hispanics taking the same surveys in English to report problems/disabilities in vision, speech, self-care, emotion, pain, and cognition. By contrast, no important differences were found in EQ-5D dimensions between any groups.

Meyerhoefer, C. D., and Zuvekas, S. H. (2010). "New estimates of the demand for physical and mental health treatment." Health Economics 19, pp. 297-315. Reprints (AHRQ Publication No. 10-R056) are available from the AHRQ Publications Clearinghouse.

Consumer price responsiveness is central to U.S. health care reform proposals, but the best evidence is from the RAND Health Insurance Experiment (HIE), now more than 25 years old. The researchers estimated health care demands by calculating expected end-of-year prices and incorporating them into a zero-inflated ordered probit model applied to several overlapping panels of data from 1996 to 2003. They found that the demand for outpatient mental health visits has become substantially less price elastic over the last 25 years. The RAND HIE had found that the demand for mental health visits was substantially more elastic than that for physical health visits. The new study found that the price responsiveness for mental health visits during the 1996-2003 period for the full U.S. population decreased substantially and is now slightly lower than physical health visits. The authors suggest that rapid changes in medical technology and the diffusion of managed care may, in part, account for this change.

Mularski, R. A., Campbell, M. L., Asch, S. M., and others (2010). "A review of quality of care evaluation for the palliation of dyspnea." (Contract No. 290-05-0034). American Journal of Respiratory and Critical Care Medicine 181(6), pp. 534-538.

Despite the commonness and debilitation of dyspnea (difficult or labored breathing), clinical assessment and palliation of dyspnea is sporadic, and few quality measures exist to guide dyspnea care improvement. In this dyspnea quality measure review, the researchers identified and reviewed 5 operationalized quality measures, 14 quality indicators, and clinical assessment tools in 4 categories. Because of the many etiologies and treatment options for dyspnea, they were unable to make recommendations for how treatment should be operationalized into quality measures that would reliably link to improved patient outcomes. However, they did recommend that regular reassessment after therapeutic interventions with an intensity instrument is a minimal requirement to guide palliation of dyspnea.

Osler, T., Glance, L. G., and Hosmer, D. W. (2010, March). "Simplified estimates of the probability of death after burn injuries: Extending and updating the Baux Score." (AHRQ grant HS16737). The Journal of TRAUMA Injury, Infection, and Critical Care 68(3), pp. 690-697.

The Baux Score, developed 50 years ago to predict mortality after burn injury, has become inaccurate because of advances in burn care. This Score posited that the percentage mortality risk for a burn patient was the sum of the patient's age and the number denoting the percentage of the body burned. For example, a 50-year old patient with a 50 percent burn area was considered almost certain to die. Another problem has been that this score does not take into account the effects of inhalation injury. To update the Baux Score, the researchers used data from the National Burn Registry on 39,888 patients to develop a logistic regression model containing age, total burn surface area, and inhalation injury. They determined that inhalation injury added the equivalent of 17 years (or a 17 percent burn). The researchers conclude that this rough approximation of burn severity can be calculated mentally and is an accurate prognostication that can be computed with a calculator at the bedside of burned patients.

Owens, P. L., Barrett, M. L., Gibson, T. B., and others (2010, August). "Emergency department care in the United States: A profile of national data sources." Annals of Emergency Medicine. 56(2), pp. 150-165. Reprints (AHRQ Publication No. 10-R059) are available from the AHRQ Publications Clearinghouse.

The authors describe seven publicly available data sources on emergency department care in the United States. They compare and contrast their methods of sampling, types of data collected, definitions, and assumptions. There were some systematic differences among the data sources. Some were more suitable for understanding hospital-level characteristics, others for detailed clinical- and visit-level data. Data sources differed somewhat on global estimates for fundamental variables, such as the number of emergency departments and the number of visits. The sources discussed were the American Hospital Association Annual Survey Database, the Hospital Market Profiling Solution, the National Emergency Department Inventory, the Nationwide Emergency Department Sample, the National Hospital Ambulatory Medical Care Survey, the National Electronic Injury Surveillance System—All-Injury Program, and the National Health Interview Survey.

Parekh, A. K., Barton, M. B. (2010). "The challenge of multiple comorbidity for the U.S. health care system." The Journal of the American Medical Association 303(13), pp. 1303-1304. Reprints (AHRQ Publication No. 10-R061) are available from the AHRQ Publications Clearinghouse.

Approximately 75 million people in the United States have two or more coexisting chronic conditions. The knowledge base for interrelated or unrelated but concurrent illnesses is limited, because patients with comorbidities are excluded from both epidemiologic studies and therapeutic trials. One area in which some initial progress is being made to reduce the burden of multiple chronic conditions on society is advancing evidence-based clinical decisionmaking in the care for patients with comorbidities. In 2007, the Agency for Healthcare Research and Quality sought proposals for studies with a focus on persons who have multiple chronic conditions. Grants funded under this program are already underway. Some subjects of research are how comorbid illnesses affect therapy and outcomes for patients with diabetes, depression, and eight prevalent chronic conditions, and the use of preventive services in patients with multiple illnesses.

Patterson, M. E., Hernandez, A. F., Hammill, B. G., and others (2010, March). "Process of care performance measures and long-term outcomes in patients hospitalized with heart failure." (AHRQ grant HS10548). Medical Care 48(3), pp. 210-216.

This study examined how overall conformity to the five Centers for Medicare and Medicaid Services (CMS) heart failure-specific process measures is associated with individual-level, long-term outcomes (1-year mortality and cardiovascular readmission) in a broad group of patients in the United States. Included in the study were 22,750 Medicare fee-for-service beneficiaries who were enrolled in a heart failure program between March 2003 and December 2004. The study found that hospital conformity rates varied from 52 to 86 percent across the CMS process measures. With the exception of the positive association between hospital-level conformity to the assessment of left ventricular function and cardiovascular readmission, there were no associations between the CMS hospital performance measures or the composite measures and patient-level mortality or cardiovascular readmission rates at 1 year.

Patterson, P. D., Huang, D. T., Fairbanks, R. J., and Wang, H. E. (2010). "The emergency medical services safety attitudes questionnaire." (AHRQ grant HS13628). American Journal of Medical Quality 25(2), pp. 110-115.

Patient safety in the emergency medical services (EMS) setting has received little study and thus is poorly understood. The researchers evaluated the feasibility of adapting the Safety Attitudes Questionnaire to the EMS setting, examined the reliability and validity of the instrument, and evaluated score variation across different EMS agencies in a metropolitan area. They administered the survey instrument to three advanced life support EMS agencies in the Pittsburgh area. Ratings were developed for six patient safety domains: safety climate, job satisfaction, perceptions of management, teamwork climate, working conditions, and stress recognition. Results showed that instrument utility was generally positive. The six domains revealed acceptable model fit and validity and the proportion of positive perceptions varied significantly across EMS agency sites for five of the six domains.

Popescu, I., Werner, R. M., Vaughan-Sarrazin, M. S., and Cram, P. "Characteristics and outcomes of America's lowest-performing hospitals: An analysis of acute myocardial infarction hospital care in the United States." (AHRQ grant HS16478). Circulation Cardiovascular Quality and Outcomes 2(3), pp. 221-227.

Hospitals that have poor compliance with five measures of care quality for treating heart attacks (aspirin on admission, aspirin at discharge, beta blocker on admission, beta blocker at discharge, and angiotensin-converting enzyme inhibitor/ angiotensin receptor blocker use at discharge for patients who have left ventricular dysfunction) tend to have lower bed numbers, lower staffing ratios, lower patient volumes, and worse mortality rates than hospitals that comply better with the five care measures. Low-performing hospitals also tend to be safety-net hospitals for vulnerable populations, and are less likely to provide specialty services, such as coronary revascularization. The authors suggest that these low performers are ripe for policy and quality improvement efforts to gain better patient outcomes and reduce disparities.

Rose, D. E., Tisnado, D. M., Malin, J. L., and others (2010, February). "Use of interpreters by physicians treating limited English proficient women with breast cancer: Results from the provider survey of the Los Angeles Women's Health Study." (Interagency agreement between AHRQ and the National Cancer Institute). HSR: Health Services Research 45(1), pp. 172-194.

The researchers surveyed 348 physicians who had been identified by a population-based sample of breast cancer patients about physician-reported use and availability of interpreters. Almost all had treated patients with limited English proficiency in the 12 months preceding the survey. Fewer than half of the physicians reported good availability of trained medical interpreters or telephone language interpretation services when needed. The overwhelming majority used bilingual staff not specifically trained in medical interpretation and patients' friends or family members. Compared with physicians working in health maintenance organizations, physicians working in solo practice and single-specialty medical groups were less likely to report using trained medical interpreters or telephone language interpretation services. This was also true of physicians in county government or medical school/university settings.

Skolasky, R. L., Mackenzie, E. J., Riley, L. H., and Wegener, S. T. (2009). "Psychometric properties of the Patient Activation Measure among individuals presenting for elective lumbar spine surgery." (AHRQ grant HS16106). Quality of Life Research 18, pp. 1357-1366.

Variability in outcome after lumbar spine surgery is well documented. Some of this variation may be due to the individual's propensity to engage in adaptive and rehabilitation behaviors. To explore this issue, the researchers sought to determine the psychometric properties and construct validity of the Patient Activation Measure (PAM) in a group of 283 individuals undergoing lumbar spine surgery. The 13-item PAM scale is a participant-completed questionnaire that addresses factors such as self-efficacy and condition-specific knowledge and skills. The researchers found its construct validity and correlation with optimism, hope, self-efficacy, and locus of control (as measured by other survey instruments) was strongly positive. The researchers concluded that the PAM is a reliable and stable measure in this population, has high test-retest reliability, and possesses good internal consistency of the individual scale items.

Slutsky, J., and Clancy, C. (2010, March). "Patient-centered comparative effectiveness research." Archives of Internal Medicine 170(3), pp. 403-404. Reprints (AHRQ Publication No.10-R049) are available from the AHRQ Publications Clearinghouse.

Patient-centered comparative effectiveness research (CER) is essential for high-quality care because it focuses on filling gaps in evidence that is needed by clinicians and patients to make informed decisions. This commentary reviews recent developments in CER and their implications for clinicians and patients. In 2009, an investment of $1.1 billion for CER was made through the American Recovery and Reinvestment Act, creating an unprecedented opportunity to develop a vital enterprise through the development of unbiased and timely evidence to inform important decisions facing clinicians and patients. The Institute of Medicine also published a report in 2009 outlining the priorities for CER. These events afford an opportunity to reexamine and reevaluate how best to approach patient-centered research. CER has to link the production of relevant research with strategies for delivering evidence to the point of care. Health information technology offers the potential of linking practice and research in unprecedented ways. In pursuing these new opportunities, patient-centered CER should take into account individuality, values, innovations, and equity.

Warren, M. D., Arbogast, P. G., Dudley, J. A., and others (2010). "Adherence to prophylactic antibiotic guidelines among Medicaid infants with sickle cell disease." (AHRQ grant HS16974). Archives of Pediatric and Adolescent Medicine 164(3), pp. 298-299.

Infants with sickle cell disease have as much as a 100-fold increased rate of pneumococcal infection compared with the general population. Treatment with penicillin has been shown to reduce the risk of pneumococcal sepsis by 64 percent. Thus sickle cell management guidelines include twice daily penicillin doses for infants and young children. Using retrospective data from the Tennessee Medicaid program, the researchers identified 407 infants with sickle cell disease, of whom 60 percent did not receive antibiotic prescriptions by the age of 12 weeks. Having one or more risk factors significantly increased nonadherence to guidelines. Risk factors included having a single mother, maternal age younger than 20 years, maternal education of less than 12 years, familial income in the lowest quintile, and urban residence.

Page last reviewed September 2010
Internet Citation: Research Briefs: Research Activities, September 2010, No. 361. September 2010. Agency for Healthcare Research and Quality, Rockville, MD.